When planning a stormwater system for any commercial or civil development in Victoria, one critical factor is the fall of the drainage pipes. Also referred to as the gradient or slope, the fall ensures that water flows efficiently through the pipe network, preventing pooling, blockage, and long-term damage.
So, what exactly is the required fall for drainage pipes in Victoria?
Understanding Pipe Fall
The fall refers to how much a pipe slopes over a given distance, and it's usually expressed as a ratio (e.g., 1:100) or in millimetres per metre (e.g., 10mm/m). The greater the fall, the steeper the slope and the faster water can flow.
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Minimum Pipe Fall in Victoria
In line with Victorian plumbing regulations and industry standards like AS/NZS 3500 and AS/NZS 5065, the recommended minimum falls are:
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Stormwater pipes (less than 150mm diameter): Minimum fall of 1:100 (10mm per metre)
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Larger diameter pipes (>150mm): May require a reduced fall, depending on application, but must still allow self-cleaning velocities (usually >0.7m/s)
Local councils may also specify additional requirements, particularly in built-up or flood-prone zones. Always check with the relevant Water Authority or your project's civil engineer.
Why Pipe Fall Matters
An insufficient fall can lead to:
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Water pooling or backflow
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Increased debris buildup
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Poor site drainage and erosion issues
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Non-compliance with plumbing regulations
In civil construction, especially across varying Victorian terrains, managing fall is essential to ensure long-term reliability and reduce maintenance.
Using Plasgain Pipes for Smarter Drainage
At Plasgain, we manufacture dual-walled, corrugated polypropylene drainage pipes ideal for stormwater applications across Victoria. Fully compliant with AS/NZS 5065, our pipes are engineered for non-pressure applications where correct fall and flow are critical.
Key Benefits of Plasgain Drainage Pipes:
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Lightweight and easy to install on sloped or challenging terrain
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High flow efficiency with a smooth inner bore
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Durable, corrosion-resistant and made using recycled materials
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Ideal for council infrastructure, commercial sites, and large residential projects
Whether you're draining a subdivision in Drouin, managing runoff on a commercial site in Geelong, or working with a municipal team in Greater Melbourne; Plasgain’s locally made drainage pipes are a smart, sustainable choice.
Final Tip: Use Fall Wisely
The right pipe is only part of the solution; installation matters just as much. Always ensure your contractor or engineer is adhering to local Victorian standards and planning correct gradients for each stage of your stormwater system.
Need help selecting the right drainage solution for your project?
Contact Plasgain today for compliant, reliable stormwater pipes, engineered for Victoria's infrastructure needs.